Fluidic safety valves known in the prior art include, for example, German Patent No. 1 596 123 B and German Patent No. 1 600 804 A. Further safety valves not explicitly intended for a battery component are known, for example, from French Patent No. 1 529 839 A or WO 2013/093179 A1.
German Patent No. 1 596 123 B describes a fluidic safety valve. German Patent No. 1 600 804 A describes another fluidic safety valve in which an internal cell pressure causes a deformation of an elastic membrane of a rarefied-air can, opening a valve by way of a mechanism and allowing undesirable overpressure to escape.
French Patent No. 1 529 839 A describes a safety valve comprising a membrane that on one side is exposed to a pressure of a fluid and preloaded in a closed position by way of a spring. When a predetermined pressure is exceeded, the membrane moves and connects an inlet port to an outlet port.
WO 2013/093179 A1 describes a safety valve for a fuel injection system. The valve comprises a piston guided in a cylinder, a spring, an inlet port, and a radial outlet port.
German Patent Application No. 10 2012 222 870 A1 discloses fluidic safety valves and pressure relief valves that protect pressurized chambers, pressure vessels, and fluid pressure chambers against an impermissible rise in pressure. This protection occurs, for example, when a safety valve discharges gases, vapors or liquids into the atmosphere in collecting pipes or the like when a predetermined fluid pressure is reached and/or exceeded.
Such safety valves may be used in vehicle technology. For example, German Patent Application No. 10 2012 222 870 A1 discloses that in electric or hybrid vehicles, batteries or secondary elements (such as rechargeable batteries), are used as electrical energy storage elements and/or traction batteries. A plurality of individual cells or blocks can be interconnected to form a battery system. Nickel metal hydride cells, lithium ion cells or the like may be used as battery components or battery systems.
It is generally necessary to provide a safety valve as a vent valve in such battery components or battery systems. Sudden chemical reactions within the battery component, which in the event of a fault can occur quickly and unpredictably, can cause a fluid pressure, which is increased in relation to the normal operating pressure or the ambient pressure of the battery (i.e. a relative overpressure), to develop within the battery component. To protect a housing of the battery component or of the battery system from overpressure-induced damage (caused by the increased fluid pressure in relation to the normal operating pressure or the ambient pressure), an interior chamber enclosed by the housing of the battery component may be automatically depressurized by the safety valve.
In addition to reliable overpressure relief, however, the safety valve is also expected to effectively and reliably prevent an ingress of environmental influences, such as the ingress of foreign particles or water, from the surrounding battery area into the battery component during normal operation of the battery component equipped therewith, of the battery system or of a vehicle equipped therewith. Normal operation can result in comparatively strong oscillations or vibrations. It is therefore necessary for the safety valve to apply a comparatively high closing force so as to ensure maximum possible sealing against the ingress of environmental influences during normal operation. This can be achieved by way of a spring element, for example.
At the same time, however, reliable overpressure relief should be ensured. It is desirable that the safety valve opens swiftly and at a comparatively low overpressure. It can be advantageous for this purpose when only a comparatively low opening force is needed.
Initially, however, the comparatively high closing force required above must be overcome for relieving the overpressure, or for opening the safety valve, which necessitates a comparatively high opening force. In general, it may be necessary for the opening force to be higher than the closing force. As a result, there is a need to resolve these conflicting objectives.